The figure 1 billion dollars is typically abbreviated as $1B. When written out in long form, 1 billion dollars is $1,000,000,000, which is equal to 1,000 million dollars.
A billion is defined as "a cardinal number represented in the U.S. by 1 followed by 9 zeros, and in Great Britain 1 followed by 12 zeros." Since billion represents a different amount in the U.S. and Britain, the $1B abbreviation is used in the U.S. more often than in the U.K.
Additional abbreviations for the figure of 1 billion dollars include $1BN and $1bill. These can also be written as "one bill. dollars" or "one bn. dollars."